Envelope Manufacturing Process Eliminating Waste via Hem Folding
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Solution Overview
Problem
Existing envelope manufacturing processes generate waste, are limited by the speed of production, and require high technicality for machine setup and format changes, making them inefficient and difficult to adjust.
Innovation Solution
The proposed solution involves an envelope design with a pre-coupled area and a protective strip that allows for easy closure and reuse, along with a manufacturing process that eliminates waste by folding the edges to form hems and cutting the sheet without edge cuts, enabling high-speed production and easy format changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If edge cuts are made to release glue seams for envelope manufacturing, then the envelope can be assembled, but waste material is generated
Solution Approach 1:
The continuous sheet is divided into individual envelope sections by transverse cuts between sections, while the lateral edges are folded into hems that remain connected. This segmentation allows individual envelopes to be separated without cutting the lateral edges, eliminating waste generation while maintaining manufacturability.
Solution Approach 2:
Hems are formed on the lateral edges before the transverse cuts are made between sections. This preliminary folding action prepares the edges for connection, allowing the glue seams to be released and envelopes assembled without requiring waste-removing cuts on the lateral edges.
2Productivity
If traditional manufacturing processes are used, then envelopes can be produced, but production speed is limited and waste management becomes a constraint
Solution Approach 1:
The process maintains continuous production by forming hems on lateral edges that remain connected throughout the sheet, allowing uninterrupted manufacturing. The transverse cuts between sections enable easy separation of individual envelopes without stopping production or managing waste removal, thus maintaining high productivity without waste constraints.
3Adaptability or versatility
If perforation means are changed to adjust bag width, then different formats can be produced, but the adjustment process requires high technical expertise and takes a long time
Solution Approach 1:
The hem-forming mechanism serves multiple functions: it creates the lateral edge folds, prepares the surfaces for gluing, and maintains connection between sections. This universal mechanism can accommodate different sheet widths without requiring changes to perforation means, enabling quick format adjustments without technical expertise.
4Manufacturing precision
If clean cuts are made instead of tears, then perceived quality is higher, but waste is still generated for side seams
Solution Approach 1:
Instead of cutting the lateral edges to create side seams, the invention folds the lateral edges into hems and connects them. This inverted approach maintains the clean edge quality of folded hems while eliminating the need for waste-removing cuts, as the lateral edges remain connected and useful throughout the continuous sheet.
Data Source
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AI summary
The invention relates to an envelope formed from a sheet (M) of flexible material and comprising: • a lower section (12), • an upper section (11) superposed on the lower section (12), the sections (11, 12) being joined together by lateral edges (14), leaving an opening between the lateral edges (14), • a protective strip (17) on a layer of closing adhesive (170), the layer of closing adhesive (170) being intended to bring about the closure of the envelope (1) after the protective strip (17) has been removed, and at least one precut region (19) that is able to be detached from the envelope (1), the protective strip (17) and the layer of closure adhesive (170) extending at least partially over the precut region (19). Associated method and production machine